Digitech GNX4 Multiple Effects Processor / Guitar Workstation

In 1979 I built a multiple effects "box". It looked like a mixer or Moog synthesizer of the era, walnut hardwood sides, aluminum face. Tons of knobs. The idea was to combine all of the popular effects of the time (fuzz/distortion, compressor, chorus, flanger, phase-shifter, pre-amp, and a mixer) into one cabinet. It did away with all of the mess of cables, batteries (it had a 110vac power supply)....a bit a head of its time. I named it the Razorgasm. It was pretty cool.

For years I have wanted a multi-effects processor that would give all the sounds I crave. After months of searching and testing I decided on the Digitech GNX4 and the Korg PX4. The Digitech GNX4 is much more than a multi-effects processor--it is a Guitar "Workstation".

With some tweaking and correct connections (to amps and so forth), the GNX4 sounds great. A few users have complained about this and that regarding the sound quality live--chances are, they just have not explored the various setup options (Speaker Compensation, EQ, and so forth).

Amp Modeling
After owning the GNX4 for almost a year, and comparing it to other amp modelers I own or have tried, I would say the GNX4 amp modeling is middle of the road (see SuperModels below). As with most modelers, if you like the heavy-metal rectified, high-gain sound, the GNX4 does pretty well. Where it lacks IMHO is in more subtle amps and applications. Though you can get a clean sound, the clean and blues-type amps just are not quite right. They miss the warmth, thickness, and sustain of a good clean tube amp.

I also find it a bit tedious to setup an amp. The GNX4 offers cabinet (?) EQ, something I have not mastered. Luckily, Guitar One magazine provides a variety of GNX4 settings each issue. I often use these as starting points, especially EQ- wise. I prefer the much simpler approach of the VAMP or VOX Tonelab. Turn a dial to select an amp with separate controls for EQ. The GNX4 approach of multiple use buttons is fine if you're sitting at home and have some free time, but is a drag when you want to quickly select an amp and cabinet.

Effects
In regards to effects. This is where the GNX4 beats most other modelers. I am very disappointed with the POD XT Live and its supposedly great 80 effects. Unless I am missing something, and perhaps I am, the GNX4 categorically kicks the POD XT Live's butt in this regard. (Note: there are a few great POD XTL effects.)

The WAH and pickup selector settings are very useful, though to be honest, I don't use them much.

The compressor functions as well as any I have tried, something I cannot say for the myriad of stompbox compressor models of the POD XT Live. It is not just a threshold gate/cuttoff. It really seems to compress the sound and if you set the gain high, each pick of a string explodes--just like a good compressor should do. My only negative comment regarding the compressor--it does not appear to be footswitchable (on/off).

The distortion models, especially the Boss DS version sounds great. I own the Boss DS-1 and cannot tell much difference between the GNX4 model and the original when a/b switching between them.

The modulation effects blow away the POD XT Live, both in quantity and quality. The GNX4 offers the standard chorus, flanger, and phaser. They all sound fine. In addition, the GNX4 offers a triggered flanger, envelope, phase shifter, synthtalk, etc. I find applications for virtually all of these effects and no other box that I am aware of provides this quantity and quality of modulation effects.

The delay variations are good. I am not super thrilled with them, but.....

The reverb variations are also good. Again, nothing outstanding, but plenty servicable.

Looper
Once I got this to work, well it is a killer. You can spend big bucks just for a looper and its thrown in with the GNX4.

Drum Machine
Fair to good. Serves my purposes, though this an area (drum machine, drum tracks) that I am sorely lacking in talent and technique.

On Board Recorder
It's okay. Not great. The sound quality of the onboard recorder versus recording the GNX4 using the computer is night and day. Perhaps I am doing something wrong, but the onboard recorder sound quality is not great. I use it to capture riffs, ideas--perfect for that. It's also provides the looper function. Oh, and the recorder eats Flash cards quickly. Sound files are rendered as WAV files so they are huge.

Connectivity
No multi-effects box that I am aware of does a better job of acting as a mixer, providing line ins, mic in, two sets of line outs, speaker compensation, USB, MIDI, and so forth. Easy to setup, easy to use, perhaps the most important feature for my use. In comparision, the POD XTL does not have stereo line ins, does not have balanced line outs, does not have two sets of line outs, and does not push MIDI note data (for recording) through its USB interface. The BOSS GT8 does not provide two sets of line outs and does not have USB.

X-Edit
The GNX4 is bundled with XEdit, the tool used to create, modify, delete, and store GNX4 presets/patches. The tool is very well designed, is relatively easy to use, and provides full access to the inner workings and capabilities of the GNX4. It is complicated, only because the GNX4 offers so many parameters, effects, and so forth. It takes guys like Mike-Guitar3456 to fully understand and leverage the power of this tool and the GNX4.

Complaints
I have a few complaints. The tuner can be difficult to engage (must press two footswitches simultaneously) and it is not super accurate, IMHO. I much prefer my Boss TU-2 and POD XT Live tuners. I would like better amp modeling. The onboard recorder is great for quickly recording ideas, but the sound quality leaves something to be desired. Would like the JamMan feature of earlier GNX4s. Does not appear that the GNX4 X-Edit application works on workstations that are not connected to a GNX4. Finally, would like a little more mixing control.

Bottom Line
The GNX4 is perhaps the best all-around multi-effects box available today. As advertised, it is a Guitar workstation--the Swiss army knife of multi-effect boxes. Its amp modeling is not as good as the POD XT Live or VOX Tonelab, especially for those of us who don't do a lot of heavy metal (see SuperModels below). However, the rest of the package is superior--connectivity, onboard recording, onboard drum machine, and the quantity and quality of effects. The real bottom line: All of these multi-effect amp modelers require lots of time to completely figure out. Yeah, you can use them right out of the box. But you must spend lots of hours to get the most out of these boxes. Unfortunately, I don't have the time to invest like I should. Frankly, if all you are after is great sound, any of the top boxes (VOX Tonelab, POD XT, GNX4) will work just fine--you just have to put in the time.

The number of features and specs are too numerous for me to describe here. Consequently, I will leave that up to the Digitech GNX4 Brochure (PDF).

No, they are not scantily-clad beach babes. The
MFX SuperModels are simply the holy-grail of amp modeling amps, cabinets, popular artist patches, and general presets. I own or have owned five of the top amp modelers available. Before I applied the MFX SuperModels, I felt the GNX4 was just an average amp modeler. Not anymore. It took someone to really dig deep into the bowels of the GNX4 and uncover its true capability. His name, Mike or simply Guitar3456.

The MFX Supermodels are complex warped models that accurately defines the amplifier it models. Mike and his associates rented a ton of amps and took dozens of audio samples of each amp to acheive a more accurate representation of the amplifier being modeled, including gain characteristics, EQ, Sustain, and Compression--the essence of the amp's identity.

Why would anyone spend months of such tedious work? Mike tells the following story...

"When users were dismayed early on by the GNX4 basic models and posting their disappointment for firmware revisions (at the Digitech Sound Community), I thought it would be nice to have a huge library (of amp models). The problem was getting the specs to follow the amp which you cannot do with one basic model. So I sampled them (GNX4 amp models) to identify their shortcomings. That's when I decided to sample real amps and compare them using an analyzer. When I pushed further, I found that my GNX4 was awesome compared to other amp modelers (allows you to warp multiple amp models to obtain realistic results). Local guys started coming over for customizing their pedal. So one thing led to another and the Ultimate endeavor came to life. Months and months of work, equipment, rentals..."

I purchased the MFX SuperModels Ultimate package the moment it became available and frankly cannot even imagine how many hours (weeks, months) it took Guitar3456 to sample the amps and convert those samples into the hundreds of amps, cabinets, and presets that found their way to the CD.

Some of my early favorites include the artist patches (BB King, Rockman-Tom Sholz, Thin Lizzy, etc.). You could literally spend hours just working through the artist patches.

How do they sound? I have not scratched the surface yet of using these amps but those I have tested sounded great and appear to offer all of the functionality of the original modeled amp. What I mean by this is, some amp modelers claim to offer a particular amp model, but in reality it only offers perhaps the model's clean channel, hi-gain channel, or it does not offer full control of EQ, gain, volume, and so forth. It appears that the MFX SuperModels amps do provide everything the modeled amp offers. Click the following link for more amp info:
MFX SuperModels-Included Amps

Now, how much does all of this cost? I bit the bullet and purchased the Ultimate package for $115, which included shipping. You can also piece meal the deal for less than $50 per CD (three CDs). Click the following link for more information: MFX SuperModels

Do you want the most versatile and best-sounding amp modeler and multi-effects box available? The GNX4 with the MFX SuperModels amps, cabinets, and patches is it, IMHO. It just goes to show how a little digging and effort can find the hidden beauty in just about anything.

The following are a few tips from Guitar3456 regarding the use of the MFX SuperModels...
The MFX SuperModels .g4p extensions contain patch information for both red and green channels when saved to the GNX4. To setup patches using Xedit to access different amp models:

Select an AMP manufacturer folder. They contain the .acm files which are the amp/cab combination in the hypermodel. For example, select from the VOX folder. When you open it, it will contain a bunch of .acm files. Clean, Crunch, Topboost etc.

Once you selected your acm files for the red and green channels, edit your effects and assignment pages (optional).

Select Device -> save to user location ( card or user preset). This copies the patch to the GNX4.

Once you've done this a few times, it takes less than 30 seconds to make a patch and send it to the GNX4. The GNX4 is designed to open with a .g4p preset that contains all of the preset data (amps, cabs, effects, EQ, etc.). Consequently, it requires that you setup patches to change amp models. I set mine up in banks for live use. Bank 1 for example:

Marshall Plx

Marsh OD

Marsh Lead

Vox Clean

Fender Princeton

MFX SuperModel Examples
I recorded the following using the GNX4 SuperModels. Guitars, Bass, and Drums were all produced and recorded using the GNX4. To listen, click the following links:

GNX4 Comments: Cannot beat the GNX4 for all out features. On board 8-track recorder, looper, great effects (including whammy, pitch shift, envelope, LFOs), drum machine with seven kits and dozens of patterns, great connectivity (XLR, 1/4", USB, full MIDI, mic with phantom power), excellent bundled software, compact flash for recording/looping and unlimited preset storage, cab resonance & EQ, amp warping, and so forth. Great for studio and live performance. Stock amps without tweaking are okay. Presets are poor. However, knowledgeable tweakers can leverage the GNX4 power (processing & bandwidth and warp feature) to produce excellent amps and artist presets (e.g., MFX SuperModels). Due to the variety of options and layout, I find amp/cabinet selection and tweaking to be time-consuming and tedious. USB is provided for recording, MIDI, and preset control. An optional footswitch array allows hands-free recording control. Digitech provides very good email support and offers several web sites and forums to exchange ideas, presets, and music:
Main site,
Guitar Workstation,
Forum,
GNX4.org Web Site

GNX4+MFX SuperModels Comments: The price shown at the left includes the GNX4 and the MFX SuperModels Ultimate package. The Ultimate SuperModels package runs $110. It is worth it. It offers hundreds of new amps, dozens of cabinets, and hundreds of artist patches. Refer to my GNX4 review or the MFX SuperModels Web site for more information. These are not run of the mill presets. The MFX Supermodels prove that the GNX4 has the internals to produce great amps/cabinets, it just takes a lot of tweaking and experimenting.

GNX3000 Comments: I have owned the GNX3000 for a short time, so my review and comments are preliminary. The stock amps are good. With a little tweaking, they sound very good. Legendary amps for Bass guitar are also included. For some reason, the GNX3000 sounds better "live" than the GNX4. I often find with the GNX4 that what hear through headphones and recordings is not what I hear when playing through power amps and PAs. Not so with the GNX3K--in fact, it sounds better through my amps and PA. The GNX3K presets are the best I have found in an amp modeler. However, even the best preset requires some tweaking based on guitar used, venue, and playing style/preferences. And this is the rub--you cannot overwrite or save changes to the presets in the two factory banks (130 preset locations). You can edit a preset and save it to one of the 65 user preset locations, but with only 65 user locations, they're going to fill up fast. The GNX3K is missing some GNX4 features (on board recorder, compact flash port) and its looper and drum machine are scaled down. I assumed the effects quality of the GNX4/GNX3K boxes would be the same, but IMHO I feel a few of the GNX3K effects sound a bit better. Amp/cabinet selection and tweaking is tedious. The new GNX3000 SuperModels are available ($60 US) and are a great addition to the unit--however, I much prefer the GNX4 SuperModels for quanity and sound quality.USB is provided for recording, MIDI, and preset control. An optional footswitch array allows hands-free recording control. Excellent recording software is included. The small footprint of the GNX3K and its general physical layout improves on the GNX4's physical configuration. Digitech provides very good email support and offers several web sites and forums to exchange ideas, presets, and music:
Main site,
Guitar Workstation,
Forum,
MFX SuperModels

POD XTL Comments: The price and review are based on the POD XTL with model packs. As reviewed, no stock MFX box offers the variety in amps. The quality of the clean amps is good to very good, but the GNX4 with SuperModels and GNX3K are slightly better. The higain amps are very good and improve considerably with some post EQ tweaking. In fact, virtually all of the POD amps improve significantly with some careful EQ tweaking. The stock amp selection is good, but I recommend you purchase the additional model packs, especially if you're into hard rock and metal. Amp/cabinet selection and tweaking is slighltly less tedious than a GNX. The effects are good, but I prefer the GNX effects. Plus, a few key effects are missing (e.g., pitch shifting). Regarding presets, suffice it to say I have overwritten most of them. Fortunately, the XTL allows you overwrite all preset locations. You can download approximately 4,000 POD XTL compatible presets from the Line 6 Customtone web site. USB is provided for recording and preset editing. However, the XTL does not push MIDI "note" data through the USB. No recording software is included. The POD XTL and Variax software (Line 6 Edit, Variax Workbench) and the software management application (Line6 Monkey) are all downloaded from the Line6 site--it is not bundled with the hardware products. Line6 offers great support via its web site, including good forums and the customtone preset library. Oh, and if you own a Variax, purchase the XTL. It provides the means to upload Variax firmware updates, it provides power to the Variax, and it allows you to store your amp, effects, EQ, and Variax settings as XTL presets. Web resources: Line 6, ,
Custom Tone (presets), ,
Institute of Noise, ,
Vetta Ville

V-AMP Pro Comments: You can't beat the V-AMP Pro for its combination of price and ease-of-use. A few of the 32 amps are very good. The others are so-so. Cabinets are good and the direct interface provides a wealth of options and is well regarded in the industry. The effects are good, but user configurability is limited. The reverb has a some very interesting parameters. Presets are good and can be modified and overwritten. However, switching from preset to preset is very slow, perhaps a problem for live performances. The V-AMP pro offers very good connectivity options including XLR balanced outs. An optional MIDI control board with expression pedal runs $150. I highly recommend the V-AMP Pro as a second (or first) amp modelers, because of its low price and ease of use. Several forums/web sites provide a wealth of additional presets. Behringer provides very good email support. Here is a site that provides a POD2-to-VAMP patch converter: POD2 TO VAMP Preset Converter.

Tonelab Comments: The Tonelab's claim to fame is its 12AX7 tube and transformer simulation logic. It's clean amps are outstanding. Warm with clarity, color, and push. The Tonelab offers perhaps the best clean amps available in an amp modeler. The British and Boutique HiGain amps are very good. The other HiGain amps are bit too glassy and I have been unable to tweak them for the better. A few of the cabinets are outstanding. One trick is to run the Tonelab through a Behringer DI box and use the DI's speaker simulation rather than a Tonelab cabinet. It works. (Boss GT-8 users have done the same.) The quality of the effects is very good. The Tonelab offers a richness of sound that is difficult to acheive with other modelers I have used. Plus, the Tonelab is a very simple to use. One knob for amps. One knob for cabinets. Basic amp controls. Simple and it works. Stock presets are good and they may be overwritten with your custom tweaks. I have a few patches on the Tonelab that I have not been able to match on the other boxes. The Tonelab makes for a great studio, desktop amp modeler, but because of its simplicity and good live sound, would serve well in an effects rack for live performances. The Tonelab SE includes two expression pedals and footswitches and runs $500. The Patchtronix Web site provides a forum and preset library. A newer forum is geared to just the Tonelab: Tonelab Web Site

Model

Cost

Features

Clean Amp Quality

HiGain Amp Quality

Amp Variety

Effect Quality

Effect Variety

GNX4 or GNX3000?
If you have a GNX4 and the MFX SuperModels, I recommend that you do not purchase the GNX3000. After one week of switching between them, I see no advantage to owning both the GNX4 and the GNX3000, and sound quality wise, I feel the GNX4 (with the Supermodels) is superior. Evidently, the GNX3000 was intended to replace the GNX2. It is not a replacement for the GNX4. Not only does the GNX4 have many more features, evidently its sound engine is superior as well. I figured the GNX3000 with its newer modeling method would be superior, and perhaps it is compared to a stock GNX4. But tweaked, the GNX4, IMHO, is superior.

So why do I plan on keeping the GNX3000? First, I am very fond of some of its presets. Second, it blends well with the GNX4 as a second "amp". Third, I am hoping the GNX3K SuperModels will improve the box. Fourth, and probably most importantly, it serves as another sound card and MIDI interface that helps me connect everything together.

More Comparison Information
A shredder friend of mine who has been out of the loop equipment-wise, asked about amp modelers. Click the following link to access those comments:

One of the GNX4's most valuable features is that you can use it as your central connector/mixer for recording and performances. I have read a few negative comments about the GNX4's sound. I am willing to bet some of these users connected their GNX4 to the standard input of a guitar amp. Not the best setup. Think about it. The GNX4 does the sound modification and amp / speaker modeling...you don't want to color or muddy it up by running it through the guitar amp tonal circuits. I find it is best to connect the balanced L/R outs to a clean power amp, or connect the Left out to the effects loop of a guitar amp.

The following image shows how I have connected everything together. Click the image to enlarge it.

The GNX4 is bundled with Pro Tracks Plus, an OEM Cakewalk product. I find it to be a good entry-level recording application. Not too complex yet it provides decent functionality.

Something I learned....you can add tons of software VST synths and effects, many of which are freeware or downright cheap to Pro Tracks Plus. Since DXi is the native plugin model for Pro Tracks, you need a VST-DXI converter. I purchased Tonewise DirectIxer for $50 and could not be happier with its performance.

I have added 20+ synths (Rhino, M42, Synth1, etx.) and effects (distortion, delays, chorus, autopan, etc.) to Pro Tracks using DirectIXer and they work incredibly well.

To access the synths, just connect a midi keyboard (any cheap MIDI keyboard or MIDI controller will do, I use a Yamaha DX21 that I have had for a zillion years). If you don't have a MIDI keyboard, you can purchase one for less than $100. Can probably pickup a garage sale "family" keyboard with MIDI for next to nothing.

To access the effects, simply add them to the track.

One great side benefit: soundfonts. The rgaudio site offers a free soundfont player that you can add to Pro Tracks as a VST plug-in that allows you to record music played through a soundfont. Literally hundreds (probably thousands) of free soundfonts exist--samples of every conceivable instrument.